1. Field of the Invention
The present invention relates to an extractor for separating and extracting a dispersoid and a dispersion medium from a liquid sample containing the dispersoid and the dispersion medium, and an image forming apparatus employing this extractor.
2. Description of the Related Art
A technology for performing a specified process using a liquid carried on a circumferential surface of, e.g. a roller is utilized in many fields such as a printing technology. For example, such a technology is applied to a wet-type image forming apparatus using a liquid developer (e.g. copier, printer, facsimile machine or a complex machine with functions of these).
A liquid used for a process contains a dispersoid and a dispersion medium in many cases. A liquid developer containing a toner as a dispersoid and a carrier liquid as a dispersion medium is used, for example, in the above image forming apparatus. The dispersion medium takes a role in promoting uniform dispersion of the dispersoid to enable a uniform and/or stable process. In a specific process, it is desired to collect and reutilize the dispersion medium.
There is known an image forming apparatus provided with a recycling device for collecting a dispersion medium. The recycling device is so structured that a conductive roller is arranged at an inner side of a conductive pipe while defining a small clearance to the conductive pipe and a liquid developer is poured into the clearance. By forming an electric field between the conductive pipe and the conductive roller, the toner and the carrier liquid are separated and the carrier liquid is collected thereafter.
However, in the above recycling device, it takes much time to separate the toner and the carrier liquid and the recycling device cannot be installed in a wet-type image forming apparatus designed to perform a high-speed printing process. If the clearance between the conductive pipe and the conductive roller could be reduced to a level of several microns, the toner and the carrier liquid could be separated at a higher speed. However, in view of part accuracy and device construction, it is substantially impossible to cause the conductive pipe and the conductive roller to face each other with a clearance in the order of several microns therebetween.